Heavy-duty insulating support connector

ABSTRACT

Insulating support members are secured to one another in an optimized manner to resist shear forces, tensile forces, compression forces and bending moments tending to separate the members, by means of an insulating dowel extending into holes in both members and held in place by a tension member of glass roving impregnated with curable resin.

United States Patent [72] Inventors Karl F. Drexler 3,089,048 5/1963Balm et a1 310/260 Burnt Hills; 3,135,888 6/1964 Coggeshall 336/197XJames S. Bishop, Schenectady, N.Y. 3,330,978 7/1967 Pettit 310/260 [21]Appl. No. 885,723 3,344,296 9/1967 Coggeshall et al 310/260 [22] FiledDec. 17,1969 3,344,297 9/1967 Bishop et a1. 310/260 [45] Patented Feb.23, 1971 3,348,085 10/ 1967 Coggeshall et a] 310/260 [73] AssigneeGeneral Electric Company 3,437,859 4/1969 Gibbs et a1 174/ 138(.3)X

Primary Examiner-Laramie E. Askin 54] HEAVY DUTY INSULATING SUPPORTAttorneysWilliam C. Crutcher, Frank L. Neuhauser, Oscar CONNECTOR B.Waddell and Joseph B. Forman 5 Claims, 5 Drawing Figs. [52] US. Cl174/138, 310/260 [51] Int. Cl 1101b 17/00 Fleld ofseal'ch Insulatingupport members are secured to one 138-3; 310/260, 270; 336/197 anotherin an optimized manner to resist shear forces, tensile forces,compression forces and bending moments tending to [56] References Citedseparate the members, by means of an insulating dowel ex- UNITED STATESPATENTS tending into holes in both members and held in place by a ten-3,024,302 3/ 1962 Coggeshall 310/260X sion member of glass rovingimpregnated with curable resin;

M l s AIEN FEB23 lg" JAMES s. BISHOP BY M. 6 W THEIR ATTORNEY.

1 HEAVY-DUTY INSULATING SUPPORT CONNECTOR BACKGROUND OF THE INVENTIONThis invention relates generally to insulating heavy duty supportmembers and to an improved arrangement for connecting the members toresist bending moments or forces tending to disengage the members.

In heavy-duty electrical apparatus, such as very large dynamoelectricmachines or transformers, the parts are subjected to high electrical,magnetic and mechanical stresses. An example of parts subject to suchstresses is found in the end winding supports and connection ringsupports of very large generators, wherein a large number of partsconnecting the machine elements and winding supports are found. Examplesof such systems are seen in US. Pat. No. 3,089,048 issued to Hahn et al.on May 7, 1963 and U.S. Pat. No. 3,344,296 issued to Cogg eshall et al.on Sept. 26, 1967, both patents being assigned to the present assignee.The support components in such machines have typically been made out ofinsulating material such as cotton cloth or glass cloth laminates.

Tension members of resin impregnated glass roving or tape have beensuggested in the prior art, to hold insulated conductors or their spacermembers in place or to tie insulating structural or support memberstogether as exemplified in US. Pat. No. 3,024,302 to Coggeshall, U .S.Pat. No. 3,330,978 to Pettit, and US. Pat. No. 3,437,859 to Gibbs et a1.However, there has always remained a residue of hardware necessary toreinforce or connect structural joints subject to complex loading. Forthese cases, manufacturers have utilized metal hardware, which isundesirable in the vicinity of electrical and magnetic fields, orinsulating hardware, which has. a lower strength, particularly in thecase of threaded members.

Accordingly, one object of the present invention is to provide animproved heavy-duty insulating support connection for resisting high orcomplex loading tending to disengage the connected members.

Another object of the invention is to provide an improved insulatingconnection, wherein the various connector elements can be optimized withrespect to tension, compression, shear and bending to obtain fulladvantage of the strength of the individual elements.

SUMMARY OF THE INVENTION members to be joined, and a tension tie,preferably of resin-.

impregnated glass roving, holding the members together under tension andalso arranged to retain the dowel in place.

DRAWING The invention, both as to organization and method of practice,together with further objects and advantages thereof, will best beunderstood by reference to the following specification, taken inconnection with the accompanying drawings, in which:

FIG. I is a view of two insulated support members connected according toone fonn of the invention;

FIG. 2 is a cross section taken along lines Il-II of FIG. 1;

FIG. 3 is a view of an alternate embodiment of the invention;

FIG. 4 is a cross section taken along lines IV-IV of FIG. 3; and

FIG. 5 is a view, partly in section, showing another modification of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Referring toFIGS. 1 and 2 of the drawing, support components I and 2 are joinedtogether in the position shown. The exact function of members 1, 2 isimmaterial to the present invention, but they might typically be endwinding support members in a large generator or support members for thear cuate connection rings in the end turn region of such a generator ormembers in any heavy electrical apparatus subject to high electrical,magnetic, and mechanical stresses as in motors, transformers, bus bars,etc.

The material of members I, 2 can be of any of the wellltnownhigh-strength insulating materials such as cotton cloth or glass clothlaminates commercially available as Textolite 1848 or Textolite 11637,resin-impregnated glass fiber, or even wood or vitreous materials insome instances.

Members 1, 2 have coaxial holes 3, 4 therethrough in which is disposed atightly fitting dowel member 5. Dowel S is selected from a materialhaving a high resistance to shear and bending and is preferably apolyester glass fiber material which is commercially available, anexample being Glasdramatic Rod" manufactured by Polygon Plastics Inc.

A tension tie 6 of insulated high strength material is looped back andforth around the members 1 and 2 and over the projecting ends of dowel 5in a figure-eight pattern. Tension tie 6 is preferably a glass rovingmaterial commercially available, for example, as Fiberglas ContinuousK893" manufactured by Owens Coming Fiberglas Corp. However, a wovenglass fiber tape is also suitable. The roving is impregnated with asuitable curable resin, such as a resin commonly known to the trade as astyrene-bearing unsaturated polyester resin. The roving in tie 6 iswound under tension, so that when the resin is cured to a rigid state,the portions passing over the projecting ends of dowel 5 will hold itsecurely in position and prevent it from coming out of the holes 3, 4.

Referring next to FIGS. 3 and 4 of the drawing, a modified form of theinvention shows an L-shaped insulating member 7 secured to an insulatingmember 8. As before, a dowel 9 is disposed in coaxial holes 10, 11 inthe members. An insulated washer member 12 spaces the elements 7 and 8apart from one another. The length of dowel 9 is selected to be slightlyshorter than the combined lengths of holes 10 and 11 including thespacer thickness.

A first insulated tension tie 13 of the same material as previouslydescribed is wound around the members 7, 8 and arranged to close off theends of holes 10 and 11 so that the dowel 9 cannot come out.

In accordance with this embodiment of the invention, a second tensiontie 14 is wound transversely around the first tie 13 in the spaceprovided by the thickness of spacer 12. This tie serves to furthertighten tie 13 as well as to fill the space between members 7, 8 and addadditional surface area to that already provided by spacer 12 so as toabsorb compressive force between the members.

Referring to a third embodiment shown in FIG. 5 of the drawing, asupport member partially shown as 15 is connected to a ring member 16shown in cross section. Typically, a series of circumferentially spacedmembers such as 15 would be used to support the end winding structure ina large generator and the ring 16 would serve to tie members 15 togetheras well as to support the windings. Member 15 has a hole 17 arranged toreceive the loops of a tension tie 18 passing around ring 16. A dowel 19is disposed in holes 20, 21 drilled in members l5, 16 respectively. Aninsulated washer 22 serves as a spacer between the members. A secondtension tie 23 is wound around the first tension tie 18 using the spaceprovided by spacer 22 as before. Tie 23 serves to tighten the first tieas well as to fill the space between members l5, l6.

OPERATION OF THE INVENTION The structural members of FIGS. l-5 aresubjected to various forces in operation, as noted in the drawing suchas tension forces F, which tend to separate the members. Oppositelydirected compressive forces may also be present in the case of asinusoidally varying force. The members are further subjected to shearforces F, which tend to separate the members along the joining plane.Bending moments M tend to cause relative rotation between the structuralmembers as indicated on the drawing.

' In the disclosed connection, the dowel members serve to re sist shearforces F while the tension ties serve to resist tension forces F,.Further, by virtue of the tight fit of the dowels, and the cooperationbetween the dowels and the tension ties holding them in place, bendingmoments M are effectively resisted.

Embodiments of FIGS. 35 employing insulated washers and second tensionties are further effective where there are slight variations between aseries of connected members. The second tension tie provides acompressive pad which supplements the spacer, contacting the surfacesbetween the members to fill out any unevenness. 1

Since the various connector elements perform different functions, theconnection can be designed (knowing the types of forces to be exertedupon it) by optimizing the sizes and materials of the various elements.

Thus, there has been disclosed a highly effective insulated supportwhich uses no metallic elements and provides high strength connectionsfor insulated members.

It may occur to others of ordinary skill in the art to makemodifications of this invention which will remain within the concept andscope thereof and will not constitute a departure therefrom.Accordingly, it is intended that the invention be not limited by thedetails in which it has been described but that it encompass all withinthe purview of the following claims.

We claim:

l. A heavy-duty connection for insulated support members, comprising: v

first and second insulating members having first and second portionsdisposed adjacent one another, said portions defining first and secondcoaxial holes respectively;

an insulating dowel member of high shear strength tightly disposed insaid holes; and

a first tension tie comprising strands of high tensile strengthimpregnated with curable resin wound under tension about said adjacentportions and also arranged to retain said dowel in said holes, the resinbeing cured to a rigid state.

2. The combination according to claim 1 including an insulated spacerhaving a hole therethrough aligned with the first and second holes andtightly disposed between said first and second portions of the insulatedmembers with said dowel passing therethrough. I

3. The combination according to claim 2 further including a second tieof resin impregnated strands passing around said first tie in the planeof said spacer and between the first and second portions, the resinbeing cured to a rigid state.

4. The combination according to claim 1, wherein said dowel has at leastone end protruding from the first member hole on the side opposite thesecond member, said first tie passing about the protruding end to holditin position.

5. The combination according to claim 1, wherein the first member holeextends completely therethrough, and wherein said dowel has an enddisposed within said hole, the first tie being wound so as to cover thehole and retain the dowel in place.

1. A heavy-duty connection for insulated support members, comprising:first and second insulating members having first and second portionsdisposed adjacent one another, said portions defining first and secondcoaxial holes respectively; an insulating dowel member of high shearstrength tightly disposed in said holes; and a first tension tiecomprising strands of high tensile strength impregnated with curableresin wound under tension about said adjacent portions and also arrangedto retain said dowel in said holes, the resin being cured to a rigidstate.
 2. The combination according to claim 1 including an insulatedspacer having a hole therethrough aligned with the first and secondholes and tightly disposed between said first and second portions of theinsulated members with said dowel passing therethrough.
 3. Thecombination according to claim 2 further including a second tie of resinimpregnated strands passing around said first tie in the plane of saidspacer and between the first and second portions, the resin being curedto a rigid state.
 4. The combination according to claim 1, wherein saiddowel has at least one end protruding from the first member hole on theside opposite the second member, said first tie passing about theprotruding end to hold it in position.
 5. The combination according toclaim 1, wherein the first member hole extends completely therethrough,and wherein said dowel has an end disposed within said hole, the firsttie being wound so as to cover the hole and retain the dowel in place.